<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>渐变</title>
    <style>
        div{
            width: 200px;
            height: 200px;
            background-color: pink;
            border-radius: 50%;
            background-image: radial-gradient(
                50px at center center,
                pink,
                red
            );
            background-image: radial-gradient(
                50px 20px at center center,
                pink,
                red 50%
            );
            /* background-image: linear-gradient(
                red,
                green
            );
            background-image: linear-gradient(
                to right,
                red,
                green
            );
            background-image: linear-gradient(
                45deg,
                red,
                green
            );
            background-image: linear-gradient(
                red 80%,
                green
            ); */
        }
        button{
            width: 100px;
            height: 40px;
            background-color: green;
            border:0;
            border-radius: 5px;
            color:#fff;
            background-image: radial-gradient(
                30px at 30px 20px,
                rgba(255,255,255,0.2),
                transparent
            );
        }
    </style>
</head>
<body>
    <div></div>
    <button></button>
</body>
</html>